Swift 4.0 中报错Argument of '#selector' refers to instance method 'xxx' that is not exposed to Objective-C
Swift2.3中给UIBarButtonItem添加点击事件:letbtn=UIBarButtonItem(barButtonSystemItem:UIBarButtonSystemItem.add,target:self,action:#selector(action))self.navigationItem.rightBarButtonItem=btn在Swift4.0中会报错:Argume